Injuries to peripheral nerves are common in the general population. This includes prevalent conditions such as “pinched nerves” in the neck or back, caused by disc herniations, bone spurs or thickened ligaments, and carpal tunnel syndrome. When a nerve has been compressed of sufficient magnitude and duration, the usual transport up and down the nerve of various proteins and other substances may be blocked or slowed down, increasing the irritability of the nerve. Even slight nerve compression also reduces the blood flow to the nerve, which makes it more sensitive. Greater nerve compression can lead to cell death in the nerve, and subsequent re-growth, or regeneration of the nerve, after the nerve compression has been sufficiently relieved.

In cases of mild nerve injuries, function of the nerve may return within a few months, at which point the nerve irritability typically resolves, whereas in more severe cases, the regeneration process can take over a year.

Significant stress put on a paralyzed muscle through e.g. stretching or strengthening delays, and may even prevent full nerve recovery, and such treatment should not be started until the late stage of nerve regeneration, when progressive strength return can be seen. As a general rule, a muscle which has been weakened due to nerve compression should not be exercised until there is measurable return of muscle strength due to nerve regeneration, and there is minimal pain associated with the nerve injury.

A severely injured nerve may require many months before initiating any resistive exercise to the involved muscle, in order to allow for sufficient nerve healing. A less traumatized nerve may be able to tolerate light exercise within the first month.

If a nerve cannot handle the task of exercise, there may be increased pain, tingling or numbness, or even increased muscle weakness during or after the exercise. Therefore, such signs must be watched for when starting and progressing an exercise program.

When rehabilitating the neck and back, and there is remaining arm or leg tingling/numbness or residual arm or leg weakness, the muscles in the arm or leg that have been affected by the nerve injury should typically not be exercised with resistance or stretching early on. Focus should instead be put on exercising stabilizing muscles in the neck and back, in positions which provide plenty of room for the affected nerve, and to gently promote nerve mobility. With back injuries, even exercise in standing may be too much for the nerve to handle at first, whereas lying exercises can be tolerated well.

The recovering nerve can also handle lower intensity exercise better than with high intensity, so that exercises are performed with 25-30 repetitions or more, rather than 10-15 repetitions or less prior to onset of much fatigue. This can even apply to old severe nerve injuries, e.g. more than 1-2 years after the trauma, or decompressive surgery. Therefore, symptoms and muscle strength must always be measured, as the rehabilitation exercises are initiated and progressed.

This topic of how to proceed with appropriate exercise after spinal nerve roots or other peripheral nerves have been compressed or traumatized is in general poorly understood by many physical therapists and even physicians, and many clinicians fail to recognize that such nerves often need considerable time to regenerate.

If you know of anybody who has had these types of nerve injuries, it may be helpful if you forward this information to them.

Finally, I would like to wish you an enjoyable holiday season and good health into the New Year.